import java.util.Scanner;
public class  {
    public static void main(String[] args) {
        Scanner Sc = new  Scanner(System.in);
        int number = Sc.nextInt();
        boolean flag = true;
        for(int i=2; i <number; i++) {

            if (number  % i == 0) {
                flag = false;
                break;
            }
        }
            if(flag){
                System.out.println("是一个质数");
            }else{
                System.out.println("不是一个质数");
            }
            }

        }
        }


